Connection device between members of a machine

ABSTRACT

Connection device between members of a machine comprising at least one first ( 2 ) and one second ( 3 ) coupling suitable for being connected together to orientate said members of said machine in work position, the first coupling ( 2 ) comprising at least one first ( 4 ) and one second ( 5 ) toothed elements mutually mobile between an initial reference configuration and a work configuration corresponding to a predetermined orientation of said members of the machine, the second coupling ( 3 ) comprising at least two toothed elements ( 8, 9 ) fixed together with the initial configuration and mutual displacement means of the second coupling ( 3 ) with respect to the first coupling ( 2 ) suitable for taking the second coupling ( 3 ) into a connection position with the first coupling ( 2 ) once the work condition of the first coupling ( 2 ) has been reached in correspondence with a small relative displacement between the first ( 4 ) and second ( 5 ) toothed elements of the first coupling ( 2 ) equal to the difference between the sum of the pitch of two or more teeth of the first toothed element ( 4 ) of the first coupling and the sum of the pitch of two or more teeth of the second toothed element ( 5 ) of the first coupling.

The present invention refers to a connection device between members of amachine.

In particular, hereafter reference shall be made to connection devicesof the type usually used for example in machine tools for the connectionof a rotary head or else a rotary table. In other examples, such devicesare used to displace or rotate a member of a machine by a certain anglewith respect to another, for example the device can be used in marblemachines, machines for joinery, manipulators, etc.

Currently there are two types of chip machines: continuous treatmentmachines and discontinuous treatment machines.

The first (i.e. continuous treatment machines) are equipped with atreatment head or piece-carrying table the position and mutualorientation of which can be modified continuously through stepper motorscontrolled by the electronics of the machine.

Machines of this type allow even very complex treatments to be carriedout but, however they have drawbacks which in practice limit its useabove all in very heavy duty treatments.

Indeed, continuous treatment machines, during operation, generally havehigh vibrations, low chip removal and, therefore, long treatment times.

Moreover, continuous treatment machines are usually very expensive andare not very strong and a limited resolution (usually the maximumresolution that can be obtained with a continuous treatment machine isequal to 0.001°.

Discontinuous treatment chip machines, on the other hand, are realise byusing Hirth connection devices.

Hirth devices are realised through two identical discs, equipped withfront teeth, which are connected together engaging the respective teethbetween them.

The discs can be rotated with respect to each other before connection soas to be positioned as required by the treatment being carried out and,therefore, so as to position as desired the mechanical member connectedto them, usually consisting of the piece-carrying table or else thetreatment head.

The devices of the type indicated are highly used in practice since theyallow the machine members to be positioned as required for theparticular treatment being carried out and the connection between thediscs is strong and precise enough to be used even for calibratedpositioning.

Machines which use Hirth devices are usually strong, they are notaffected by vibrations and they allow large quantities of chips to beremoved at each run. However, they are not very flexible and their usebecomes all the more difficult, up to the point of becoming practicallyimpossible, when very high resolutions are desired.

Indeed, the resolution which can be obtained with conventional devicesof this type becomes greater as the number of teeth possessed by thediscs (of the same type) becomes greater.

This is due to the fact that the discs have the same number of teethand, therefore, the greater the number of teeth, the greater the numberof positions in which a disc of 360° is divided (the positions aredefined, for example, by the hollows between two teeth of a disc inwhich the teeth of the other disc insert).

This necessarily implies that to obtain greater resolution and,therefore, to divide the 360° angle into many positions it is necessaryto increase the number of teeth.

Moreover, it must be considered that the teeth must transmit a torqueand, therefore, their thickness cannot be too thin otherwise it would betoo weak and there could be the risk, if subjected to too high forces,of them breaking.

Of course, these two drawbacks combined with each other mean that inpractice as the required resolution increases the diameter needed forthe discs increases and, therefore, the bulk, the weight, etc.increases.

The technical task proposed of the present invention is, therefore, thatof realising a connection device between members of a machine whichallows the aforementioned technical drawbacks of the prior art to beeliminated.

In this technical task, a purpose of the invention is that of realisinga connection device between members of a machine which is flexible andcapable of working with very high resolution.

Another purpose of the invention is that of realising a device which isvery strong. In particular, the teeth which allow the mutual connectionof the discs are very strong and must not preferably be made very thinto increase the resolution of the device.

The last but not least purpose of the invention is that of realising adevice which is very light and not very bulky, in particular comparedwith an analogous conventional device.

The technical task, as well as these and other purposes, according tothe present invention are accomplished by realising a connection devicebetween members of a machine comprising at least one first and onesecond coupling suitable for being connected together to orientate saidmembers of said machine in work position, characterised in that saidfirst coupling comprises at least one first and one second toothedelements mutually mobile between an initial reference configuration anda work configuration corresponding to a predetermined orientation ofsaid members of said machine, said second coupling comprising at leasttwo toothed elements fixed together with said initial configuration andmutual displacement means of said second coupling with respect to saidfirst coupling suitable for taking said second coupling into aconnection position with said first coupling once said work condition ofsaid first coupling has been reached in correspondence with a smallrelative displacement between said first and second toothed elements ofsaid first coupling equal to the difference between the sum of the pitchof two or more teeth of said first toothed element of said firstcoupling and the sum of the pitch of two or more teeth of said secondtoothed element of said first coupling.

Other characteristics of the present invention are, moreover, defined inthe other claims.

Further characteristics and advantages of the invention shall becomeclear from the description of a preferred but not exclusive embodimentof the connection device between members of a machine according to thefinding, where the device is illustrated for indicating and not limitingpurposes in the attached drawings, wherein:

FIG. 1 shows an exploded perspective view of the device according to thefinding;

FIG. 2 shows a perspective view of the elements of the device accordingto the finding; and

FIG. 3 shows a side top view of two couplings coupled together.

With reference to the quoted figures, a connection device betweenmembers of a machine is shown, wholly indicated with reference numeral1.

The device 1 comprises a first and a second coupling 2, 3 suitable forbeing connected together to orientate the members of the machine in workposition.

In particular, the first coupling 2 comprises two toothed elements 4, 5mutually mobile between an initial reference configuration and a workconfiguration corresponding to a predetermined orientation of saidmembers of said machine.

Such toothed elements 4 and 5 are connected to the members of themachine which must be positioned with respect to each other.

FIG. 1 represents an example of a coupling in which the reference isdefined by the teeth 6 and 7 respectively of the elements 4 and 5 whichare aligned.

The second coupling comprises two mutually fixed toothed elements 8, 9having the initial configuration (defined by the teeth 10 and 11 alignedwith each other and aligned with the teeth 6 and 7 so as to allow themutual connection of the two couplings).

The device also comprises displacement means 12 of the second coupling 3with respect to the first coupling 2, suitable for taking the secondcoupling into a connection position with the first coupling.

The toothed elements are constructively simple and are very practical touse. However, in different embodiments the couplings have connectionmeans different from toothings such as, for example, cylindrical pinsinserted in holes, etc.

Suitably, the displacement means 12 are suitable for displacing orrotating the second coupling 3 with respect to the first coupling 2 byan amount proportional to the relative displacement of the two elements4, 5 of the first coupling 2.

As shown in the attached figures, preferably the mutually mobile toothedelements 4, 5 of the first coupling 2 have an annular configuration andare concentric and, correspondingly, the mutually fixed toothed elements8, 9 of the second coupling 3 also have an annular configuration and areconcentric.

Moreover, the mutually mobile toothed elements 4, 5 of the firstcoupling 2 have different numbers of teeth and, at the same time, themutually fixed toothed elements 8, 9 of the second coupling 3 also havedifferent numbers of teeth.

Advantageously, the inner mobile toothed elements 5 and the inner fixedtoothed elements 9 have fewer teeth than corresponding outer mobiletoothed elements 4 and outer fixed toothed elements 8.

In this way, the teeth of the inner toothed elements have a largethickness (in any case greater than the case in which the teeth of theinner elements are greater in number with respect to the teeth of theouter elements) and are, therefore, very strong.

In a different example the inner mobile toothed elements 5 and the innerfixed toothed elements 9 have a greater number of teeth thancorresponding outer mobile toothed elements 4 and outer fixed toothedelements 8.

Moreover, the inner mobile toothed elements 5 and the inner fixedtoothed elements 9 have the same number of teeth and, in the same way,the outer mobile toothed elements 4 and the outer fixed toothed elements8 have the same number of teeth.

In a preferred embodiment, the difference between the number of teeth ofthe outer mobile toothed elements 4 and of the inner mobile toothedelements 5 is greater than one and, moreover, the difference between thenumber of teeth of the outer fixed toothed elements 8 and of the innerfixed toothed elements 9 is greater than one.

For example, by realising inner mobile and fixed elements equipped with32 teeth and outer mobile and fixed toothed elements with 45 teeth, aresolution of 0.25° can be obtained.

Thus, by rotating the inner toothed element with respect to the outertoothed element of the first coupling in a certain direction by anamount equal to such a minimum resolution, the alignment between theseventh tooth of the outer toothed element and the fifth tooth of theinner toothed element of such a first coupling is recreated, then thesecond coupling is rotated by 56° in the opposite direction to thedirection of rotation of the inner toothed element of the first couplingso as to achieve the engagement with the first coupling.

Advantageously, the machine is a chip machine and the device connects apiece-carrying table and/or a treatment head and/or a piece-carryingchuck and/or a divider to a structure of the machine.

In other examples the machine is a divider or else a machine fortreating wood or marble, a grinder, a welder, a measuring instrument,machines which operate in gradual measurement, textile machines, etc. Inpractice, the device according to the present finding can advantageouslybe used in whatever mechanism, even manual, which needs to make gradualdivisions.

The operation of the connection device between members of a machineaccording to the invention is clear from that which has been describedand illustrated and, in particular, is substantially the following.

Initially, the two couplings are interfaced and the reference elementsare aligned with each other.

In practice, therefore, the two couplings are interfaced and the teeth6, 7 of the first coupling are aligned with the hollow 13 defined by theteeth 10, 11 of the second coupling 3.

In this way the two couplings 2, 3 can be connected together by makingthem translate towards each other along the axis 14.

When one wishes to change the relative orientation of piece-carryingtable or treatment head, the inner mobile element 5 is rotated, withrespect to the outer mobile element 4, by an amount which is sufficientto position the piece-carrying table or treatment head as desired.

Then, to connect the two couplings, the second coupling 3 is rotated bya predetermined amount proportional to the rotation applied to the innermobile element 5.

For example, the small displacement which it is possible to realise withthe device represented in the attached figures is equal to 2.7272°,which is realised by aligning the teeth A and B after the teeth 7, 6 andby rotating the second coupling 3 by 30° in the opposite direction toalign it with the first coupling and to allow the connection.

In this way, the reference of the second coupling 3 (i.e. the hollow 13defined by the aligned teeth 10 and 11 which are fixed with respect toeach other) is brought back aligned with the new reference of the firstcoupling (i.e. with the aligned teeth A and B), making the connectionbetween the two couplings 2, 3 possible.

Hereafter, some examples of connection devices of the type indicatedshall be described and they shall be compared with equivalentconventional devices.

In a first example, we want to realise a device that is able to obtain aresolution of 1 degree.

Thus, considering an outer toothed element with 40 teeth with an angularpitch of 9° and an inner toothed element with 9 teeth with an angularpitch of 40°, and rotating the inner toothed element with respect to theouter toothed element of the first coupling in a certain direction ofrotation by an amount equal to such a minimum resolution, the alignmentbetween the ninth tooth of the outer toothed element and the secondtooth of the inner toothed element of such a first coupling isrecreated, then the second coupling is rotated by 81° in the samedirection as the direction of rotation of the inner toothed element ofthe first coupling so as to achieve the engagement with the firstcoupling.

It must be noted that the fitting between the first and second couplingis made possible by the fact that the work configuration thus obtainedby the first coupling recreates the initial reference configuration ofthe first coupling wherein, however, in place of the teeth of theinitial reference configuration, the ninth tooth of the outer toothedelement and the second tooth of the inner toothed element of the firstcoupling are aligned.

As is clear, the minimum resolution which can be obtained is equal tothe difference between the sum of the pitch of the ninth tooth of theouter toothed element and the sum of the pitch of two teeth of the innertoothed element.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 500 millimetres (due to thesmallest possible size of the teeth for reasons strength and the numberof teeth necessary).

Using the device according to the finding, on the other hand, toothedelements having an outer diameter of about 70 millimetres aresufficient.

In a second example we want to realise a device that is able to obtain aresolution of 0.5 degrees.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 600 millimetres, whereas usingthe device according to the finding toothed elements having an outerdiameter of about 70 millimetres are sufficient.

In a third example we want to realise a device that is able to obtain aresolution of 0.25°.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 1000 millimetres, whereas usingthe device according to the finding toothed elements having an outerdiameter of about 100 millimetres are sufficient.

In a fourth example we want to realise a device that is able to obtain aresolution of 0.1°.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 3000 millimetres, whereas usingthe device according to the finding toothed elements having an outerdiameter of about 125 millimetres are sufficient.

In a fifth example we want to realise a device that is able to obtain aresolution of 0.05°.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 5500 millimetres, whereas usingthe device according to the finding toothed elements having an outerdiameter of about 180 millimetres are sufficient.

In a sixth example we want to realise a device that is able to obtain aresolution of 0.01°.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 25,000 millimetres, whereasusing the device according to the finding toothed elements having anouter diameter of about 240 millimetres are sufficient.

In a seventh example we want to realise a device that is able to obtaina resolution of 0.005°.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 50,000 millimetres, whereasusing the device according to the finding toothed elements having anouter diameter of about 500 millimetres are sufficient.

In an eighth example we want to realise a device that is able to obtaina resolution of 0.001°.

Thus, considering an outer toothed element with 625 teeth and an innertoothed element with 9 teeth, and rotating the inner toothed elementwith respect to the outer toothed element of the first coupling in acertain direction of rotation by an amount equal to such a minimumresolution, the alignment between the fifty-first tooth of the outertoothed element and the forty-seventh tooth of the inner toothed elementof such a first coupling is recreated, then the second coupling isrotated by 29,376° in the same direction as the direction of rotation ofthe inner toothed element of the first coupling so as to achieve theengagement with the first coupling.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 250,000 millimetres, whereasusing the device according to the finding toothed elements having anouter diameter of about 550 millimetres are sufficient.

In a ninth example we want to realise a device that is able to obtain aresolution of 0.0005°.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 500,000 millimetres, whereasusing the device according to the finding toothed elements having anouter diameter of about 1000 millimetres are sufficient.

In a tenth example we want to realise a device that is able to obtain aresolution of 0.0001°.

Thus, considering an outer toothed element with 3125 teeth and an innertoothed element with 1152 teeth, and rotating the inner toothed elementwith respect to the outer toothed element of the first coupling in acertain direction of rotation by an amount equal to such a minimumresolution, the alignment between the 963^(rd) tooth of the outertoothed element and the 355^(th) tooth of the inner toothed element ofsuch a first coupling is recreated, then the second coupling is rotatedby 1,109,376° in the same direction as the direction of rotation of theinner toothed element of the first coupling so as to achieve theengagement with the first coupling.

Using a conventional device toothed elements would have to be realisedhaving an outer diameter equal to about 2,500,000 millimetres, whereasusing the device according to the finding toothed elements having anouter diameter of about 2400 millimetres are sufficient.

The present finding also refers to a machine tool equipped with thedevice described previously.

The machine tool comprises a connection device between its members whichcomprises a first and a second coupling suitable for being connectedwith each other to mutually orientate the members in work position.

The first coupling comprises at least two toothed elements mutuallymobile between an initial reference configuration and a workconfiguration corresponding to a predetermined orientation of themembers of the machine tool.

The second coupling comprises at least two mutually fixed toothedelements having the initial configuration and displacement means of thesecond coupling with respect to the first coupling suitable for takingthe second coupling into a connection position with the first coupling.

In practice, it has been noted how the connection device between membersof a machine according to the invention is particularly advantageousbecause it is very precise and strong, it allows completereproducibility, it has substantial resolution and, at the same time, ithas low bulk and weight.

The connection device between members of a machine thus conceived issusceptible to numerous modifications and variants, all covered by theinventive concept. Moreover, all of the details can be replaced withothers which are technically equivalent.

In practice, the materials used, as well as the sizes, can be whatever,according to the requirements and the state of the art.

1. Connection device between members of a machine comprising at leastone first and one second coupling suitable for being connected togetherto orientate said members of said machine in work position,characterised in that said first coupling comprises at least one firstand one second toothed elements mutually mobile between an initialreference configuration and a work configuration corresponding to apredetermined orientation of said members of said machine, said secondcoupling comprising at least two toothed elements fixed together withsaid initial configuration and mutual displacement means of said secondcoupling with respect to said first coupling suitable for taking saidsecond coupling into a connection position with said first coupling oncesaid work condition of said first coupling has been reached incorrespondence with a small relative displacement between said first andsecond toothed elements of said first coupling equal to the differencebetween the sum of the pitch of two or more teeth of said first toothedelement of said first coupling and the sum of the pitch of two or moreteeth of said second toothed element of said first coupling.
 2. Deviceaccording the previous claim, characterised in that said displacementmeans are suitable for mutually displacing said second coupling withrespect to said first coupling by an amount proportional to the relativedisplacement of the two elements of the first coupling.
 3. Deviceaccording to claim 1, characterised in that said mutually mobile toothedelements of said first coupling have an annular configuration and areconcentric and, correspondingly, said mutually fixed toothed elements-ofsaid second coupling have an annular configuration and are concentric.4. Device according to claim 1, characterised in that said mutuallymobile toothed elements of said first coupling have different numbers ofteeth.
 5. Device according to claim 1, characterised in that saidmutually fixed toothed elements of said second coupling have differentnumbers of teeth.
 6. Device according to claim 1, characterised in thatinner mobile toothed elements and inner fixed toothed elements have lessteeth than corresponding outer mobile toothed elements and outer fixedtoothed elements.
 7. Device according to claim 1, characterised in thatsaid inner mobile toothed elements and said inner fixed toothed elementshave the same number of teeth and, in the same way, said outer mobiletoothed elements and said outer fixed toothed elements have the samenumber of teeth.
 8. Device according to claim 1, characterised in thatthe difference between the number of teeth of said outer mobile toothedelements and of said inner mobile toothed elements is greater than oneand, moreover, the difference between the number of teeth of said outerfixed toothed elements and of said inner fixed toothed elements isgreater than one.
 9. Device according to claim 1, characterised in thatsaid machine is a chip machine.
 10. Device according to claim 1,characterised in that said device connects a piece-carrying table and/ora treatment head and/or a piece-carrying chuck and/or a divider to astructure of said machine.
 11. Machine tool comprising a connectiondevice between its members comprising at least one first and one secondcoupling suitable for being connected together to orientate said membersof said machine in work position, characterised in that said firstcoupling comprises at least one first and one second toothed elementsmutually mobile between an initial reference configuration and a workconfiguration corresponding to a predetermined orientation of saidmembers of said machine tool, said second coupling comprising at leasttwo toothed elements fixed together with said initial configuration anddisplacement means of said second coupling with respect to said firstcoupling suitable for taking said second coupling into a connectionposition with said first coupling once said work condition of said firstcoupling has been reached in correspondence with a relative displacementbetween said first and second toothed elements of said first couplingequal to the difference between the sum of the pitch of two or moreteeth of said first element of said first coupling and the sum of thepitch of two or more teeth of said second toothed element of said firstcoupling.
 12. (canceled)